Conventionally, in designing knitted fabrics of kitted products, methods of representation for making knitted fabrics such as knitting stitch symbols or knitting symbols defined by, for example, JIS L 0200 of the Japanese Industrial Standard, are used. The knitting stitch symbols are symbols indicating textures of various knitting stitches such as front knitting stitches, back knitting stitches, front tuck knitting stitches, back tuck knitting stitches, float stitches and transfer stitches. The knitting symbols are symbols indicating the order of knitting with a needle corresponding to each knitting stitch symbol. The methods of representation for making knitted fabrics designate individual knitting stitch constituting a knitted fabric, and according to this designation, knitting data for making a knitted fabric with an automatic flat knitting machine can be generated.
The applicant has proposed in Japanese Unexamined Patent Publication JP-A 60-71748 (1985) a technique for generating knitting data for an automatic flat knitting machine with color codes represented that are substituted for the knitting stitch symbols. Substituting color codes for the knitting stitch symbols makes it easy to design a knitted fabric by image processing with a computer, and textures of more kinds of knitting stitches can be displayed on displaying means, using a large number of colors.
The applicant also has proposed in Japanese Unexamined Patent Publication JP-A 7-70890 (1995) a technique for generating loop images of knitting stitches constituting a knitted fabric by simulation, utilizing data for making a knitted fabric, and displaying the simulated images of the knitted fabric. Furthermore, in Japanese Unexamined Patent Publication JP-A 9-111617 (1997), a technique for disintegrating image data into a plurality of layers and allowing display of the priority and grouping of the layers so as to facilitate designing when performing knit design for generating data for making a knitted fabric has been proposed.
In the case of performing knit design, when the methods of representation for making a knitted fabric are used, the displayed images do not necessarily reflect faithfully the appearance of the actual knitted fabric that is knitted according to the data for making a knitted fabric. Therefore, a designer who designs a knitted fabric with data for making a knitted fabric has to have an ability of imagining the appearance of the actual knitted fabric in designing, and the knitted fabric cannot be designed intuitionally.
When the simulation of a knitting stitch loop proposed in JP-A 7-70890 is used, it is possible to design an actual knitted fabric intuitionally. In this technique, image processing is performed in the following manner. Image data of knitting yarns are stored in advance, and the shape and the position of each loop of knitting stitches, the brightness of each portion and the like are determined based on data for making a knitted fabric, and the loop is divided into a plurality of segments, and synthesized as a loop corresponding to segmented image data of the knitting yarn. Therefore, the process takes time, and the followingness of image display with respect to an operation of design modification or the like is not sufficient. In a knitted fabric knitted by an actual flat knitting machine, the shape of a knitting stitch in an earlier knitted course is transformed by the effect of the shape of a knitting stitch in a later knitted course. However, such transformation cannot be reflected appropriately.